Clinical and mechanical analysis of Tremoflo C2 vs C100 in asthmatic patients 2-7 years

Abstract

Background: Tremoflo C2 is an effort-independent oscillometer successor to C100 and measures resistance and reactance. Our objectives are to assess the reliability between two devices, compare small airway dysfunction (SAD) identification in young asthmatic children, and evaluate device acceptance, feasibility and usability in this age group.

Methods: In 53 asthmatic children 2-7 years, three sets of valid measurements were obtained for R7, R7-19, AX, and X7. SAD was defined as z-scores exceeding 1.645 residual standard deviations. After completion, patients and operators provided feedback. Mechanical analog data were obtained on four test loads at 5-37 and 7-41 Hz, using C2 and C100. Single measure intraclass correlation coefficient (ICC) determined whether C2 was as acceptable as C100. Bland-Altman analyses examined agreement and proportional bias. The McNemar test evaluated whether the proportion of SAD patients differed significantly between the two tools.

Results: In our study population, 84.9% had mild asthma and 86.8% were well-controlled. Overall ICC indicated good device reliability, and proportional bias was seen only for R7-R19 (β=0.214 (95% CI .039, .388), p=.017). SAD was identified in 47.2% using the C2 device, 49.1% with the C100, (p=1.00). Patients and operators preferred C2 over C100. Mechanical analog data showed high ICC for resistance and reactance.

Conclusion: In our young, predominantly well-controlled, mild asthmatics, the C2 and C100 devices showed good agreement, usability, and preferability of C2 to identify SAD. Although some proportional bias was seen, mechanical analog data showed high ICC, confirming strong overall agreement between devices.